1. Field of Invention
This invention relates to transmission line coupling devices for high frequency transmission lines, such as used for microwaves. Particularly, the invention relates to rotatable transmission line coupling in which the rotatable member is mechanically coupled to the outside of the transmission line system for performing a variety of functions. Typical applications are that of a waveguide coupling which rotates the plane of polarization of the waves transmitted through the device by external rotary energy source means, or the rotary coupling of a rotary joint that provides rotational position of the coupled line to external rotary position sensing means.
2. Description of Prior Art
Many different arrangements have been used to mechanically rotate the plane of polarization of a transmitted high frequency wave. For example, the amplitude modulator disclosed in the patent to Murphy U.S. Pat. No. 2,880,399, and the rotary polarization coupling disclosed in the patent to Augustin U.S. Pat. No. 4,528,528, and many patents divulging differing linear polarization coupling probe shapes in the circular waveguide of devices patented after Augustin. However, all of these devices have a rectangular waveguide orthogonal to a circular waveguide such that the symmetric rotation of the probe in the rectangular waveguide causes the other end of the probe in the circular waveguide to rotate to the desired polarization. The rotary energy is coupled by external means, by direct contact with the polarizing probe in the case of Murphy, and by a plastic insulator in the case of Augustin.
All of these prior devices require that the rectangular waveguide have a specific orientation with respect to the circular waveguide; namely, they must be orthogonal to each other and with their axes intersecting. None of the previous devices lend themselves to the direct coupling to an external coaxial transmission line without an intervening waveguide type transmission line.
The previous devices are all necessarily larger because of their requirement for a rectangular waveguide.
All of the previous polarization type devices define a specific probe shape in the circular waveguide or specific circular waveguide characteristic.
None of the previous devices lend themselves to direct coupling to coaxial line or other transmission line forms without an intervening rectangular waveguide type transmission line.
In the case of a rotary joint type device, no prior art was found in which the coupled coaxial line center conductor is mechanically coupled to external position sensing means.
All of the previous devices described a system rather than a fundamental element with a wide variety of applications.